is a very small bacterium
in the class Mollicutes
This class of organisms lack a peptidoglycan cell wall
present on all other firmicute
bacteria. Instead, it has a cell membrane
which incorporates sterol
compounds, similar to eukaryotic cells
. It obtains these sterols from the host serum, allowing it to retain a simple structure. Lacking a cell wall
, these organisms are resistant to the effects of penicillins
and other beta-lactam antibiotics, which act by disrupting the bacterial cell wall.
has one of the smallest genomes
known, with 816 kilobase pairs
(kbs). Its genome and proteome
has been fully characterized. It uses some unique genetic code, making its code more similar to mitochondria than to other bacteria. Thus it is said that Mycoplasma pneumoniae
has a degenerate genome. It lacks the cellular machinery for making many essential compounds, including new purines
. It also has no tri-carboxylic acid cycle
and an incomplete electron transport chain
. Because of this, it is an obligate parasite
and is never found free-living.
was historically known as "Eaton's agent". Because it is a major cause of pneumonia in people over the age of 65, M. pneumoniae
has also earned the name "The Captain of the Men of Death".
Mycoplasma pneumonia is a form of bacterial pneumonia which is caused by bacteria of the Mycoplasma genus.
is spread through respiratory droplet transmission
. Once attached to the mucosa of a host organism, M. pneumonia
extracts nutrients, grows and reproduces by binary fission
. Attachment sites include the upper and lower respiratory tract, causing pharyngitis
. The infection caused by this bacterium is called atypical pneumonia
because of its protracted course and lack of sputum production and wealth of extra-pulmonary symptoms. Chronic mycoplasma infections have been implicated in the pathogenesis of rheumatoid arthritis
and other rheumatological diseases.
infections can be differentiated from other types of pneumonia by the relatively slow progression of symptoms, a positive blood test for cold-hemagglutinins in 50-70% of patients after 10 days of infection (cold-hemagglutinin-test should be used with caution or not at all since 50% of the tests are false-positive), lack of bacteria in a gram-stained sputum sample, and a lack of growth on blood agar.
Mycoplasma atypical pneumonia can be complicated by Stevens-Johnson syndrome
, hemolytic anemia
or Guillain-Barré syndrome
Second generation macrolide
and second generation quinolones
are effective treatments. Disease from mycoplasma is usually mild to moderate in severity.